A clear estimate in a few steps.
Measure the space you want to cover. For a rectangular area, enter its length and width. For a circular area, choose Circle and enter the diameter—the distance all the way across its center. Enter the additional depth of material you need, rather than the total depth of any existing layer.
Use “Add another area” for separate beds, sections of a driveway or parts of an L-shaped space. Avoid overlapping sections: the calculator adds every area you enter. Each section can have a different depth.
Set the bag volume to match your product if you are buying bags. We round the final number of bags up to whole bags. If you are ordering loose mulch, use the cubic yard result instead.
Here’s the math.
There are 12 inches in a foot and 27 cubic feet in a cubic yard, so the conversion factor is 12 × 27 = 324. For a circle, replace length × width with π × (diameter ÷ 2)². For metric measurements, volume in cubic meters is length × width × depth in centimeters ÷ 100; divide that volume by 0.764554857984 to get cubic yards.
A worked example
A 20-foot-long, 10-foot-wide area filled 3 inches deep needs 600 ÷ 324 = 1.852 cubic yards before allowance. With a 5% allowance, that becomes approximately 1.944 cubic yards. At 2 cubic feet per bag, the result is 27 whole bags.
How much will one cubic yard cover?
These theoretical coverage figures assume an even layer, with no allowance for losses or compaction.
| Layer depth | Coverage per yd³ |
|---|---|
| 1 inch | 324 square feet |
| 2 inches | 162 square feet |
| 3 inches | 108 square feet |
| 4 inches | 81 square feet |
| 6 inches | 54 square feet |
Know what the estimate leaves out.
Real ground is uneven. Material can settle, compact or spill. The default 5% allowance is a starting assumption you control; it is not a compaction factor or an installation specification. Ask your supplier or installer what is suitable for your project. Price results multiply your material quantity by your entered price and exclude delivery, taxes and labor.
For tree mulch rings, University of Georgia Extension describes a 2–3 inch layer. Planting type and existing mulch affect what you should add. Keep mulch away from the trunk and use local guidance for your plants.
Good questions. Straight answers.
How do I calculate cubic yards?
For a rectangle measured in feet with depth in inches, multiply length × width × depth and divide by 324. For a circle, multiply π × (diameter ÷ 2)² × depth and divide by 324. Add the volumes of separate areas, then apply any allowance.
How many bags of mulch are in a cubic yard?
One cubic yard is 27 cubic feet, equivalent to 13.5 bags of 2 cubic feet or 9 bags of 3 cubic feet. When purchasing 2-cubic-foot bags for one cubic yard, round up to 14 whole bags.
Does the result include extra material?
Yes. The initial allowance is 5%, which you can change from 0% to 50%. The result shows both measured volume and your allowance. This setting is a planning assumption, not a recommendation for every installation.
Can I calculate a project in meters?
Yes. Choose Meters & cm, enter length and width in meters and depth in centimeters. Changing units converts measurements already entered. Results include cubic yards and cubic meters; gravel weight is labeled in US tons.
Is the cost an actual supplier quote?
No. Enter a price from your supplier to estimate material cost. Delivery, tax, labor, minimum orders and supplier rounding are excluded. No prices are fetched automatically.
Calculations run in your browser. Read our calculation methodology or get help measuring your project.